Major - P3 There are identical definitions of the UnshardedCollection class in metadata_manager.cpp and collection_sharding_state.cpp, and I think only the one in collection_sharding_state.cpp is actually used:
class UnshardedCollection : public ScopedCollectionMetadata::Impl { public: UnshardedCollection() = default; const CollectionMetadata& get() override { return _metadata; } private: CollectionMetadata _metadata; }; const auto kUnshardedCollection = std::make_shared<UnshardedCollection>();